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Genetic Architecture of Skin and Eye Color in an African-European Admixed Population
Open accessAbstract
Variation in human skin and eye color is substantial and especially apparent in admixed populations, yet the underlying genetic architecture is poorly understood because most genome-wide studies are based on individuals of European ancestry. We study pigmentary variation in 699 individuals from Cape Verde, where extensive West African/European admixture has given rise to a broad range in trait values and genomic ancestry proportions. We develop and apply a new approach for measuring eye color, and identify two major loci (HERC2[OCA2] P = 2.3 × 10(-62), SLC24A5 P = 9.6 × 10(-9)) that account for both blue versus brown eye color and varying intensities of brown eye color. We identify four major loci (SLC24A5 P = 5.4 × 10(-27), TYR P = 1.1 × 10(-9), APBA2[OCA2] P = 1.5 × 10(-8), SLC45A2 P = 6 × 10(-9)) for skin color that together account for 35% of the total variance, but the genetic component with the largest effect (~44%) is average genomic ancestry. Our results suggest that adjacent cis-acting regulatory loci for OCA2 explain the relationship between skin and eye color, and point to an underlying genetic architecture in which several genes of moderate effect act together with many genes of small effect to explain ~70% of the estimated heritability.
Overview
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TL;DR
This study maps skin and eye color in 699 Cape Verdeans, an African-European admixed population, using genotype- and ancestry-based association approaches. It finds distinct genetic architectures: a few major loci plus average genomic ancestry explain much of skin color variation, while eye color is dominated by HERC2[OCA2] with a secondary SLC24A5 signal.
Key findings
- Two major eye-color loci were identified: HERC2[OCA2] rs12913832 (P = 2.3×10−62) and SLC24A5 (P = 9.6×10−9 in the abstract; Table 1 reports rs2470102 genotype P = 4.8×10−10), affecting both blue versus brown eyes and shades of brown.
- Four major skin-color loci were identified: SLC24A5 (P = 5.4×10−27), TYR/GRM5 (P = 1.1×10−9), APBA2[OCA2] (P = 1.5×10−8), and SLC45A2 (P = 6×10−9); together they account for 35% of total skin-color variance, while average genomic ancestry accounts for ∼44%.
- Skin and eye color have different architectures: skin color correlates with African genomic ancestry at R² = 0.44, whereas eye color correlates weakly with ancestry (R² = 0.08) and with skin color (R² = 0.14).
- At 15q13.1, the eye-color signal in HERC2[OCA2] and the skin-color signal in APBA2[OCA2] are genetically separable, with weak linkage disequilibrium between peaks (R² = 0.112), suggesting adjacent cis-regulatory effects on OCA2.
Methods
- Studied 699 Cape Verdeans from six islands; final analyses used 685 individuals with skin reflectance and 625 with high-quality eye photographs. Genotyping used Illumina 1M, yielding 903,837 autosomal SNPs after QC.
- Skin color was measured as a modified melanin (MM) index by reflectance spectroscopy on the upper inner arm; eye color was measured as a new quantitative “T index” derived from digital photographs and a principal curve.
- Association analyses used additive linear regression adjusted for sex and first three principal components, plus ancestry-based mapping with SABER+, EMMAX mixed models, imputation with MaCH, CMS selection scores, and power simulations.
Limitations
- The paper states that CEU and YRI are imperfect proxies for the true ancestral populations of Cape Verde, which likely include multiple Southern European and West African groups, and cautions that “European” and “African” should not imply homogeneity.
- The authors note that GCTA-style heritability estimation was not used because the genetic relationship matrix is inflated by population structure and pilot studies showed large sampling variability in this moderate-sized sample.
- The paper states that failure to replicate some previously reported loci (e.g., ASIP, KITLG, MC1R) could reflect limited ancestral allelic variation, incomplete ancestry correction in earlier studies, or effects too small to detect; the APBA2[OCA2] regulatory mechanism remains a hypothesis requiring functional validation.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“No additional loci were found in conditional analyses that adjust for the most significant SNPs in the known loci (four for skin and two for eye color).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“For skin color, we used reflectance spectroscopy on the upper inner arm to calculate a modified melanin (MM) index, which appears normally distributed with a mean of 7.39 and standard deviation of 0.85 for the Cape Verde cohort.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“We observed that RGB reflectance values project onto an empirical curve that begins and ends, respectively, with very light blue, and very dark brown eyes”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“the 15q13.1 association signal for eye color, which lies ∼50 kb upstream of OCA2 in an intronic region of HERC2”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“In analyses adjusted only for principal components and sex, the signals at 15q21.1 (for skin color, Figure 3a) and 15q13.1 (for eye color, Figure 3b), dominate the significance plots.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“there is only a weak correlation between skin and eye color in Cape Verdeans (R∧2 = 0.14)”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“The correlation between skin color and African genomic ancestry (R∧2 = 0.44) is apparent both across and within (Table S1) islands clusters”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“For example, in a model with 3 major skin color genes that act additively and equally, we predict an R∧2<0.3 between African genomic ancestry and skin color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“Overall, African genomic ancestry in Cape Verdeans ranges from 23.5% to 87.9%, with a median of 58%.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic admixture in Cape Verdeans
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Neither amino acid substitution is predicted to dramatically alter protein function”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“a missense alteration in TYR, S192Y (rs1042602) [11] (Figure 4b), is in linkage disequilibrium with the most significant SNP in GRM5 (rs10831496) in this sample”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [11] MD Shriver, 2003, Skin pigmentation, biogeographical ancestry and admixture mapping, Hum Genet source
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In the paper
“The two remaining skin color loci at 11q14.3 and 15q13.1 exhibit the strongest association signals within intronic regions of GRM5 (Figure 4b) and APBA2 (Figure 4d)”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“the peak of skin color association in APBA2 is separated from OCA2 by ∼1 Mb”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“and African genomic ancestry is also weakly correlated (R∧2 = 0.08) with eye color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“approximately half of the European chromosomes we examined carry an ancestral HERC2 (OCA2) haplotype together with a derivative APBA2 (OCA2) haplotype, or vice versa”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
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In the paper
“alleles of the four major loci shift the MM index 0.16–0.33 units”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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In the paper
“By contrast, very little evidence for positive selection is apparent in the GRM5-TYR region (Figure 4b).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Selection for pigmentary loci
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In the paper
“considerably less than the proportion of variance attributed to individual genomic ancestry, 44%”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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In the paper
“genotype of the four major loci together with individual ancestry accounts for 57% of total variation.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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In the paper
“the sum of effect sizes for homozygous substitution at all four loci would shift, in an individual, an amount about the same as ∼1/3 of the total range of skin color we observed”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Strength:hedged· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIn the paper
“and IRF4, MC1R, SLC24A4, TYRP1, reported previously to affect skin color in populations of European ancestry [4], [6].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Power to detect additional loci
What the sources say
- Not checked yetcites [4], [6]
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In the paper
“In addition to the major eye color locus at HERC2 (OCA2), there is a second eye color locus at 15q21.1 whose position corresponds to the SLC24A5 A111T allele”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Notably absent from the four skin color loci detected in this study are ASIP and KITLG, reported previously to affect skin color in populations with African-European admixture [12], [15]”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Power to detect additional loci
What the sources say
- Not checked yetcites [12], [15]
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In the paper
“the most highly associated SNP at each of the four skin color loci (Table 1) exhibits frequency differences of 0.99 (SLC24A5), 0.80 (APBA2 [OCA2]), 0.74 (SLC45A2), and 0.56 (GRM5-TYR).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Selection for pigmentary loci
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In the paper
“For skin color, population-attributable variances of SLC24A5, GRM5-TYR, APBA2 (OCA2), and SLC45A2 are 18%, 7%, 9% and 7%, respectively”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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In the paper
“the distribution of P values for SNPs in both types of candidate genes overlaps with that of randomly chosen genomic regions.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Power to detect additional loci
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In the paper
“Although eye color and skin color are correlated, their underlying genetic architecture in Cape Verde is very different.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Like APBA2 (OCA2), SLC24A5, and SLC45A2, SNPs in KITLG exhibit large CEU-YRI allele frequency differences of 0.7–0.99.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“By contrast, the “rest of the genome” (beyond APBA2 (OCA2), GRM5-TYR, and SLC24A5) has a very strong influence on skin color, nearly twice that of all four single loci combined.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Our work confirms the very strong effect of rs12913832 on eye color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Our analysis of skin color genetic architecture generally assigns smaller contributions to individual genes than in previous work.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“In our work, the effect size of SLC24A5 corresponds to 13% of the range of skin color variation in Cape Verde”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“but provides little evidence for an effect on skin color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“we estimate an effect size for a single SLC24A5 allele in Cape Verde that corresponds to 4.9 melanin units”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“since neither the transcribed region of OCA2 nor HERC2 has a major influence on skin color in Cape Verde.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“and we did not detect KITLG as a skin color locus.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Instead, the 15q13.1 skin color locus maps to an intronic region of APBA2 that lies ∼1 Mb away from OCA2”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Beyond HERC2 (OCA2) and SLC24A5, individual genomic ancestry has relatively little effect on eye color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“In 1000 simulations, the correlation between genome-wide ancestry and the simulated phenotype has a mean of 0.27 with a standard deviation of 0.037.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: Residual non-genetic variance is independent of any genotype or ancestry.
- The authors state this as an assumption: The simulated phenotype has a genetic architecture with three major loci, each with the same effect as SLC24A5 and perfectly ancestrally informative.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the 15q21.1 region harbors coding sequence variation in SLC24A5 that affects skin and eye color similarly”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“Thus, the effect of the 11q14.3 locus on skin color could be mediated by a combination of regulatory and coding variation.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“For eye color, we developed a new measure based on automated analysis of digital photographs that captures the full range of African-European variation.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“Thus, the European alleles probably represent hypomorphic alterations that compromise melanogenesis, leading to decreased pigmentation.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
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In the paper
“Taken together with similar results from EMMAX (Figure S1), these results suggest adequate correction for population structure.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“Overall, these observations point to different genetic architectures for skin and eye color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
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In the paper
“and is higher than anticipated for a trait determined by the action of a small number of genes.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Variation in human skin and eye color is substantial and especially apparent in admixed populations, yet the underlying genetic architecture is poorly understood because most genome-wide studies are based on individuals of European ancestry.”
- Also stated in: § Introduction · plain
“But our knowledge of skin and eye color genetics is incomplete, based mostly on the limited range of phenotypic diversity represented by individuals of European ancestry [4]–[10], or on candidate gene studies in African Americans [11]–[15].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Abstract
What the sources say
- Not checked yetcites [4]–[10]
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Also stated in: § Introduction · plain
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“All three approaches—genotype-based association, ancestry-based association, and a mixed model—point to the same set of genetic loci.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic admixture in Cape Verdeans
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“but the 15q13.1 region harbors two distinct peaks of regulatory sequence variation that act separately on skin and eye color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Previous studies of skin color estimate narrow sense heritability at 70%–90% of total variation [40]”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
What the sources say
- Not checked yetcites [40] PJ Byard, 1981, Quantitative genetics of human skin color, Am J Phys Anthropol source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesWhat the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“For a genome-wide significance level (P<5×10−8), the results of our simulations reveal >90% power to detect an effect size of 0.21 MM (Figure 5a), which is 4.1% of the total range of skin color observed in our sample”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Power to detect additional loci
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Still, there is strong experimental evidence that the HERC2 region represents regulatory variation that acts via OCA2 [33]”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [33] M Visser, 2012, HERC2 rs12913832 modulates human pigmentation by attenuating chromatin-loop formation between a long-range enhancer and the OCA2 promoter, Genome Res
Strength:boosted· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These observations are consistent with the presence of discrete CMS peaks under the HERC2 (OCA2) and APBA2 (OCA2) regions (Figure 4d) and suggest that the loci may have undergone selection independently in European populations.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Our results indicate that Cape Verdean pigmentary variation is the result of variation in a different set of genes from those determining variation within Europe”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Introduction
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, the effects of HERC2 and APBA2 are genetically and statistically separable.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“these estimates, based on conventional regression analyses in which individual genomic ancestry is considered as a covariate, fail to consider admixture stratification, wherein admixture proportions vary widely due to recent admixing, and genotypes at unlinked loci remain correlated.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“indicating that variation at these loci affects different shades of brown eye color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“suggest that long-range regulatory effects help to explain the relationship between skin and eye color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Introduction
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These results suggest that an APBA2 (OCA2) mutation conferring light skin arose before the spread of humans out of Africa”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We considered whether the skin color GWAS signal for APBA2 might simply reflect linkage disequilibrium with HERC2 and OCA2, but rejected that hypothesis for several reasons.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and that a HERC2 (OCA2) mutation conferring pale eye color arose much later.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“KITLG remains a good candidate gene”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesNone of the sources cited for this claim have been checked yet.
In the paper
“This eye color locus was later refined to a small region 50 kb upstream of OCA2 in an intron of the HERC2 gene [7], [8], [10].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [7] M Kayser, 2008, Three genome-wide association studies and a linkage analysis identify HERC2 as a human iris color gene, Am J Hum Genet source
- Not checked yetcites [8] Liu F, Wollstein A, Hysi PG, Ankra-Badu GA, Spector TD, et al.. (2010) Digital quantification of human eye color highlights genetic association of three new loci. <comment>doi:10.1371/journal.pgen.1000934</comment> source
- Not checked yetcites [10] RA Sturm, 2008, A single SNP in an evolutionary conserved region within intron 86 of the HERC2 gene determines human blue-brown eye color, Am J Hum Genet source
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIn the paper
“Finally, our population genetic analysis of HERC2 and APBA2, together with similar work on the HERC2 - OCA2 interval from Donnelly et al. [37], is consistent with the possibility that blue eyes were selected independently from fair skin for reasons having to do with reproductive success rather than survival.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [37] MP Donnelly, 2012, A global view of the OCA2-HERC2 region and pigmentation, Hum Genet source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“loss-of-function for OCA2 can cause blindness due to loss of melanin from retinal pigment epithelial cells [31]”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [31] MH Brilliant, 2001, The mouse p (pink-eyed dilution) and human P genes, oculocutaneous albinism type 2 (OCA2), and melanosomal pH, Pigment Cell Res source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“Neither functional nor expression studies suggest a role for the APBA2 protein in pigmentation [42]–[44]”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [42]–[44]
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIn the paper
“For SLC24A5, this apparent discrepancy stems from whether effect sizes are described as a fraction of the “average pigmentation difference between European-Americans and African Americans of about 30 melanin units” [13], or the entire dynamic range within a population, which is 77 melanin units in Cape Verde.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [13] RL Lamason, 2005, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, Science source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“however, any effect in the Cape Verde population is too small to be detected in our sample.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesA conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“By contrast, the observations of Miller et al. on the effects of KITLG in an African-American sample used a relatively small set of admixture informative markers to correct for genomic ancestry, which may have led to an overestimation of effect size.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesWhat the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“We also note that genome-wide ancestry proportions estimated using CEU and YRI in frappe are highly correlated (r>0.988) with the first principal component computed on Cape Verdean genotypes alone without using any ancestral individuals.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Characterization of genetic admixture
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“To support the statement that correlation between skin color and African genomic ancestry (R2 = 0.44) is much higher than expected for a trait determined by the action of a small number of genes, we performed simulations using the observed genotype and ancestry information in the Cape Verde individuals.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the presence of admixture stratification, population-attributable variance for multiple loci sums to more than unity, because genotypes at unlinked loci are correlated with each other and with genome-wide ancestry.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIn the paper
“Based on a combination of simulation and theory, we have previously established a genome-wide significant criterion of p<7×10−6 for this ancestry-based mapping approach [51].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
What the sources say
- Not checked yetcites [51] H Tang, 2010, Joint testing of genotype and ancestry association in admixed families, Genet Epidemiol source
Load-bearingStrength:boosted· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The first PC is highly correlated with African genomic ancestry estimated using frappe (r = 0.99).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Characterization of genetic admixture
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passes- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
In the paper
“in previous work on admixed populations from Mexico [24], we have found that accurate local ancestry estimates can be obtained using imperfect ancestral populations (including CEU and YRI), as long as the haplotype phasing is accurate.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Characterization of genetic admixture
What the sources say
- Not checked yetcites [24] NA Johnson, 2011, Ancestral components of admixed genomes in a Mexican cohort, PLoS Genet source
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passes
- It may state two separate claims as one. 58
- The quote only partly states this claim. 1
- Probably not a substantial claim. 23
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For genotype-based association, four skin color loci (5p13.3, 11q14.3, 15q13.1, and 15q21.1) and two eye color loci (15q13.1 and 15q21.1) met genome-wide criteria for significance, P<5.7×10−8”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the most strongly associated SNPs at 5p13.3 and 15q21.1 represent missense alterations in two well-known pigmentary genes, SLC45A2 L374F (Figure 4a) and SLC24A5 A111T (Figure 4c)”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“GRM5 and APBA2 lie 396 kb upstream and 1025 kb upstream of TYR and OCA2, respectively”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
In the paper
“in a randomly sampled African-American cohort from the Family Blood Pressure Study (FBPP) [21], African genomic ancestry ranges from 40.6% to 99.3%, with a median of 89.5%”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic admixture in Cape Verdeans
What the sources say
- Not checked yetcites [21] H Tang, 2006, Racial admixture and its impact on BMI and blood pressure in African and Mexican Americans, Hum Genet source
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesThe quote only partly states this claim.
- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Across different islands, the distributions of African genomic ancestry exhibit substantial overlap in range but vary in their median values, from 50.5% in Fogo to 74.4% in the capital island of Santiago”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic admixture in Cape Verdeans
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The 5p13.3 and 11q14.3 regions affect only skin color (Figure 4a, 4b), whereas the chromosome 15 regions (15q13.1 and 15q21.1, Figure 4c, 4d) affect both skin and eye color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Ancestry-based association yields broader peaks than genotype-based association, but the distribution of significant regions is strikingly consistent for the two approaches, uncovering the identical set of six loci”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“in analyses that consider TYR and GRM5 SNPs as covariates, both remain significant (P = 3.7×10−6 for rs10831496; P = 0.00012 for rs1042602).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Each derived allele is present on a single major extended haplotype (>160 kb in length for HERC2 (OCA2) and >90 kb in length for APBA2 [OCA2]), whereas the ancestral alleles are found on multiple, shorter, haplotypes.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“in conditional regression analyses where genotypes at both loci are included as covariates, HERC2 does not affect skin color if eye color is also included as a covariate (HERC2 P = 0.48, APBA2 P = 0.0009); conversely, APBA2 does not affect eye color if skin color is also included as a covariate (APBA2 P = 0.083, HERC2 P<2×10−16).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For eye color, the ancestral HERC2 (OCA2) allele is mostly dominant over the derived allele, consistent with the near recessive mode of inheritance of blue eye phenotype in Europeans”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The four skin color loci we identified by association analysis act in an additive fashion: we found no evidence of dominance at any of the loci, nor evidence of opposite-sign epistasis between loci.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The SLC45A2 and APBA2 (OCA2) GWAS signals coincide with sharp CMS signals (Figure 4a, 4d); broader CMS signals are also apparent at SLC24A5 and HERC2 (OCA2) (Figure 4c, 4d).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Selection for pigmentary loci
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The derived APBA2 (OCA2) allele is present at low frequencies in most populations of African ancestry, and at high frequencies in most populations of Asian and European ancestry.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“measures of linkage disequilibrium between the two loci are not significant (R∧2 = 0.036, D′ = 0.071 with Χ2 = 0.517), extended haplotypes for the derived alleles are separated by ∼800 kb”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the subset of 592 Cape Verdeans whose T-index >0.15 (Figure 1, Figure 2), both loci remain highly significant (HERC2 rs12913832, P = 5.23×10−16; and SLC24A5 rs2470102, P = 1.12×10−10)”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“By contrast, the effects of SLC24A5 on eye color are semi-dominant, and no interaction was found between this gene and HERC2”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the proportions of phenotypic variance attributed solely to genotype at each of the four major skin color loci are quite small, about 2% each for GRM5-TYR, APBA2 (OCA2), and SLC45A2, and about 7% for SLC24A5.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“By contrast, the derived HERC2 (OCA2) allele is absent from African and East Asian populations, and appears at high frequency only in Western and Northern Europe”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic and evolutionary relationships of eye and skin color genes at 15q13.1
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“even though individual ancestry contributes 44% to skin color variation, about half of that contribution (22% of the total) could also be accounted for by genotype at the four major loci.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the four major loci contribute a total of 35% to skin color variation, but only 13% above that which could also be accounted for by individual ancestry.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The GWAS significance peaks for eye color and skin color at 15q13.1 appear distinct (Figure 4d), and linkage disequilibrium between the two significance peaks is weak (R∧2 = 0.112 in our sample).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
Load-bearingStrength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“even though SLC24A5 and SLC45A2 lie on different chromosomes, their genotypes in the Cape Verde population are correlated with genomic ancestry and, therefore, with each other.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The final dataset consists of 685 individuals with skin reflectance measurements, of which 625 have high-quality digital eye photographs.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
Tests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“and has a haplotype set, linkage disequilibrium architecture, and signature of selection that is clearly distinct from the HERC2 (OCA2) eye color locus.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
Load-bearingStrength:boosted· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“After applying all quality control filters, 903,837 autosomal SNPs were available for analysis, of which 24,478 had minor allele frequency (MAF) <0.01.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the Cape Verde sample, we used dense genotype data (>900,000 SNPs) to correct for genomic ancestry, and only the first three loci exhibited a significant association with skin color.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Our results do not exclude the possibility that variation in KITLG affects skin color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Effect sizes shown in Figure 5 and Figure 7 for APBA2 (0.155) GRM5-TYR (0.193), SLC24A5 (0.334), and SLC45A2 (0.166) are from a linear regression of the Cape Verde skin color data in which genomic ancestry and genotypes at the four major loci are included as covariates.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Power calculations and estimates of effect size
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In the paper
“To evaluate potential secondary signals, we also carried out an association scan conditioning at all index SNPs, and found no evidence for secondary signals except in the GRM5-TYR region (rs10831496 and rs1042602, respectively) as described in the conditional analysis section of the Results.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
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In the paper
“By comparison, MM in individuals of European ancestry is smaller and much more narrowly distributed, with a mean of 5.38 and standard deviation of 0.27 [23].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Quantitative assessment of pigmentary phenotypes
What the sources say
- Not checked yetcites [23] SI Candille, 2012, Genome-wide association studies of quantitatively measured skin, eye, and hair pigmentation in four European populations, PLoS ONE source
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In the paper
“the direction of effect is consistent across all groups, with the derived allele associated with lighter skin color or a lower T-index”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“After removing SNPs surrounding these six loci, the genomic control parameters were 1.02 and 1.00 for skin color and eye color, respectively.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“The genome-wide association results described below are based on a linear regression adjusting for the first three principal components (PC) but the same model adjusting for up to 10 PCs does not qualitatively alter our results.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic admixture in Cape Verdeans
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- Rests on an assumption: HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“As described below, these signals correspond to SLC24A5 for skin color and HERC2 (OCA2) for eye color”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Mapping loci associated with skin and eye color
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In the paper
“thought to encode membrane transport proteins that promote melanogenesis [13], [25]–[27].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [13], [25]–[27]
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In the paper
“expression of both genes is pigment cell-specific, and null mutations dramatically impair melanin synthesis in model organisms [13], [28], [29].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [13], [28], [29]
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In the paper
“We study pigmentary variation in 699 individuals from Cape Verde, where extensive West African/European admixture has given rise to a broad range in trait values and genomic ancestry proportions.”
- Also stated in: § Introduction · plain
“In this population, extensive genetic admixture between the African and European ancestral populations during the last several centuries [16], [17] has facilitated assortment of pigmentary alleles.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Abstract
What the sources say
- Not checked yetcites [16], [17]
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- Also stated in: § Introduction · plain
In the paper
“has been well recognized to account for Mendelian-like inheritance of blue vs. brown eye color in populations of European ancestry [7], [8], [10].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [7], [8], [10]
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In the paper
“two well-known pigmentary genes for which a complete loss-of-function causes albinism in humans and in other animals [30]–[32].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Refinement of pigmentation loci by imputation and conditional analysis
What the sources say
- Not checked yetcites [30]–[32]
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, in any particular individual, genomic ancestry has predictive value for genotype at each of the four major skin color loci, and vice versa.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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In the paper
“If skin color in Cape Verde is 80% heritable, the four major loci and individual ancestry explain most of that variation, with only a small amount of “missing heritability””
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Genetic architecture of pigmentary variation in Cape Verde
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- The authors state this as an assumption: Skin color in Cape Verde is 80% heritable.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the failure to replicate previously reported effects could be due to a paucity of allelic variation in the Cape Verde ancestral populations (e.g. MC1R), incomplete correction for genomic ancestry with small panels of ancestry informative markers in the earlier studies (e.g. ASIP, KITLG), or real effects of these loci that are too small to detect in our study.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Results > Power to detect additional loci
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None of the sources cited for this claim have been checked yet.
In the paper
“OCA2 was originally considered a strong candidate gene for Afro-European pigmentary variation based on allele distribution patterns of closely linked SNPs [11], [14], [34], [35], and because of a strong association with blue vs. brown eye color in populations of European ancestry [4], [41].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [11] MD Shriver, 2003, Skin pigmentation, biogeographical ancestry and admixture mapping, Hum Genet source
- Not checked yetcites [14] HL Norton, 2007, Genetic evidence for the convergent evolution of light skin in Europeans and East Asians, Mol Biol Evol source
- Not checked yetcites [34], [35]
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In the paper
“Previous genome-wide studies of human skin and eye color have focused on populations of European ancestry and have been based primarily on categorical and subjective assessment of pigmentary phenotype [4]–[7].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [4]–[7]
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In the paper
“Hardy-Weinberg equilibrium was not used as a quality filter due to the admixed nature of the subjects.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
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In the paper
“compared to 4.8 melanin units estimated by Lamason et al. [13] in an African-American sample.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [13] RL Lamason, 2005, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, Science source
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In the paper
“SNPs with genotyping call rate <95%, SNPs showing replication errors across 20 replicated samples, SNPs in which the apparent heterozygosity was equal to one, and SNPs for which only a single allele was called in the Cape Verde dataset were removed from the analyses.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
Strength:plain· not yet calibratedn = 20Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If, however, a chromatin loop does form between APBA2 and OCA2, the BP3 region must be contained within that loop.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
Strength:plain· not yet calibratedCausal:conditional· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✗ Based: failsProbably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
In the paper
“Identity-by-states (IBS), estimated using all autosomal SNPs in PLINK [47], revealed 12 pairs of cryptic relationships (IBS>0.8). One individual from each pair was excluded.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
What the sources say
- Not checked yetcites [47] S Purcell, 2007, PLINK: a tool set for whole-genome association and population-based linkage analyses, Am J Hum Genet source
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None of the sources cited for this claim have been checked yet.
In the paper
“SLC24A5 and KITLG have been reported to have effect sizes that correspond to 25%–38% and 20%–25% of the European-West African difference in skin color, respectively [13], [15].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [13] RL Lamason, 2005, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, Science source
- Not checked yetcites [15] CT Miller, 2007, cis-Regulatory changes in Kit ligand expression and parallel evolution of pigmentation in sticklebacks and humans, Cell source
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In the paper
“Admixture stratification is important in this context because the very same loci that underlie trait differences in ancestral populations are also among the strongest admixture informative markers; therefore, incomplete correction for genomic ancestry will lead to overestimation of the effects for any locus that itself is an admixture informative marker.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“Very recently, Visser et al. [33] showed that the critical SNP in this region, rs12913832, is part of an enhancer that forms a chromatin loop with the OCA2 promoter, and that the derivative allele causes reduced recruitment of the chromatin remodeler HLTF, leading to reduced binding of additional transcription factors and impairment of loop formation and OCA2 expression in cultured human melanocyt”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [33] M Visser, 2012, HERC2 rs12913832 modulates human pigmentation by attenuating chromatin-loop formation between a long-range enhancer and the OCA2 promoter, Genome Res
Strength:boosted· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
In the paper
“Hypopigmentation associated with these conditions is thought to be caused by hemizygosity for OCA2 [46] and is therefore independent of any potential cis-acting regulatory region in APBA2.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [46] RA Spritz, 1997, Hypopigmentation in the Prader-Willi syndrome correlates with P gene deletion but not with haplotype of the hemizygous P allele, Am J Med Genet source
Strength:hedged· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
In the paper
“the ∼1 Mb interval between HERC2 and APBA2 contains a cluster of segmental duplications that serves as a frequent deletion breakpoint (BP3) involved in Prader-Willi and Angelman syndromes [45].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
What the sources say
- Not checked yetcites [45] AJ Makoff, 2007, Detailed analysis of 15q11–q14 sequence corrects errors and gaps in the public access sequence to fully reveal large segmental duplications at breakpoints for Prader-Willi, Angelman, and inv dup(15) syndromes, Genome Biol source
Strength:plain· not yet calibratedCausal:direct· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
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In the paper
“Two samples with call rate below 95% were removed.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Study population and genotyping QC
Strength:plain· not yet calibratedn = 2Tests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We favor the latter alternative, which supports a view of skin color genetic architecture that is multimodal, in which many genes of small effect cumulatively explain the correlation between skin color and individual ancestry, and together with several genes of moderate effect (GRM5-TYR, APBA2 (OCA2), SLC45A2, and SLC24A5), account for high overall heritability.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Discussion
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In the paper
“The extracted irises were manually inspected and found sufficiently accurate.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Phenotypes
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In the paper
“age was found not correlated with the phenotypes (P>0.5 for both skin and eye colors), and hence was not included as covariate.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“Effect sizes shown in Figure 5 for KITLG (0.19 MM–0.26 MM) are estimated from Miller et al. [15] in which the beta value for rs642742 is reported as 3.8 melanin units based on a linear regression model, and 2.8 melanin units based on ADMIXMAP.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Power calculations and estimates of effect size
What the sources say
- Not checked yetcites [15] CT Miller, 2007, cis-Regulatory changes in Kit ligand expression and parallel evolution of pigmentation in sticklebacks and humans, Cell source
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We note that the PAV is non-additive; in other words, variance accounted by two loci is not the sum of the PAV of the two loci individually.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
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In the paper
“We also carried out an association analysis with the program EMMAX [22], which adjusts for population stratification by including a relationship matrix as a random effect; the results (Figure S1) were similar to those obtained using conventional association analysis (Figure 3).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
What the sources say
- Not checked yetcites [22] HM Kang, 2010, Variance component model to account for sample structure in genome-wide association studies, Nat Genet source
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In the paper
“To exclude the possibility that the association between skin color and genome-wide ancestry is due to geographic confounding between islands, we examined this correlation within each island (Table S1).”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
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- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
In the paper
“Similarly, the effect size shown in Figure 5 for ASIP (0.24 MM) is estimated from 3.5 melanin units based on data in Bonilla et al. [12].”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Power calculations and estimates of effect size
What the sources say
- Not checked yetcites [12] C Bonilla, 2005, The 8818G allele of the agouti signaling protein (ASIP) gene is ancestral and is associated with darker skin color in African Americans, Hum Genet source
Strength:hedged· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✗ Load-bearing: fails✓ Based: passesProbably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, while the CEU and YRI are imperfect ancestral populations, they do not cause a large bias in either genome-wide or local ancestry estimates.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Characterization of genetic admixture
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesIt may state two separate claims as one.
- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
In the paper
“However, the genetic relationship matrix based on allele sharing is inflated by population structure [55]; in addition, in pilot studies we observed a large sampling variability of GCTA-estimated heritability due to the moderate size of the Cape Verde sample.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
What the sources say
- Not checked yetcites [55] SR Browning, 2011, Population structure can inflate SNP-based heritability estimates, Am J Hum Genet source
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In the paper
“Assessment and control for population stratification is described in Results; the P values reported in Table 1 and are derived from linear regressions using PLINK in which the first 3 principle components and sex are included as covariates.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
Load-bearingStrength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes✓ Load-bearing: passes✓ Based: passesProbably not a substantial claim. It may state two separate claims as one.
- The authors state this as an assumption: The Cape Verdean population has two ancestral populations (European and West African).
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“This approach preserves a realistic level of correlation structure between phenotype, genome-wide ancestry proportions and genotypes, and also takes into account the two strongest predictors of phenotype: genome-wide ancestry and genotype at SLC24A5.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Power calculations and estimates of effect size
Strength:plain· not yet calibratedCausal:correlational· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
- The authors state this as an assumption: Residual non-genetic variance is independent of any genotype or ancestry.
- The authors state this as an assumption: The simulated phenotype has a genetic architecture with three major loci, each with the same effect as SLC24A5 and perfectly ancestrally informative.
In the paper
“Imputed genotypes were inferred with the MaCH 1.0.16 package [52] using combined CEU and YRI haplotypes as reference; we report SNPs whose predicted R∧2 between true and imputed genotypes >0.80.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Imputation, selection signature, and haplotype analysis
What the sources say
- Not checked yetcites [52] Y Li, 2010, MaCH: using sequence and genotype data to estimate haplotypes and unobserved genotypes, Genet Epidemiol source
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In the paper
“We restricted the association scans to the 879,359 autosomal SNPs with MAF>0.01; SNPs achieving a P<5.7×10−8 were considered genome-wide significant.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Association and admixture mapping
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In the paper
“In simulation studies, the ARHMM achieves comparable accuracy as HapMix [49], but is more flexible and does not require information about the recombination rate.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Characterization of genetic admixture
What the sources say
- Not checked yetcites [49] AL Price, 2009, Sensitive detection of chromosomal segments of distinct ancestry in admixed populations, PLoS Genet source
Strength:plain· not yet calibratedTests✓ Asserted: passes✓ Checkable: passes? Load-bearing: unclear✓ Based: passesIt may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In our situation, if we code G1 and G2 to represent the derived (pigmentation lightening) alleles at the two loci, then cov(G1, G2)>0 due to admixture linkage disequilibrium, γ1γ2>0, and we have V12<(V1+V2), as is indicated by the overlapping areas in Figure 7.”
§ Genetic Architecture of Skin and Eye Color in an African-European Admixed Population > Materials and Methods > Genetic architecture
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The paper relies on this without support.
The true ancestral populations for Cape Verde likely include contributions from several areas of Southern Europe and several areas of West Africa.
“We also note that the true ancestral populations for Cape Verde are likely to include contributions from several areas of Southern Europe, and several areas of West Africa.”
The authors state this as an assumption.
Skin color in Cape Verde is 80% heritable.
“If skin color in Cape Verde is 80% heritable, the four major loci and individual ancestry explain most of that variation”
The paper relies on this without support.
HapMap CEU and YRI individuals adequately represent the European and African ancestral populations of Cape Verde.
“Data from CEU and YRI HapMap individuals [19] was used to partition each Cape Verdean individual's ancestry into “European” and “African” components.”
The authors state this as an assumption.
The Cape Verdean population has two ancestral populations (European and West African).
“assuming two ancestral populations”
The authors state this as an assumption.
Residual non-genetic variance is independent of any genotype or ancestry.
“The residual non-genetic variance was assumed to be independent of any genotype or ancestry, such that the total variance in each simulated phenotype matches that observed for skin pigmentation in Cape Verde.”
The authors state this as an assumption.
The simulated phenotype has a genetic architecture with three major loci, each with the same effect as SLC24A5 and perfectly ancestrally informative.
“The phenotypes were simulated assuming a genetic architecture with three major loci, each of which has the same effect as SLC24A5 and is perfectly ancestrally informative.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“multiple lines of evidence suggest that differences in skin pigmentation across populations have evolved primarily in response to ultraviolet radiation [17,20–22].”
From Investigating the case of human nose shape and climate adaptation (2017) · cites this paper as [17]
In the citing paper
“Interestingly, the heritability of skin pigmentation is very low in Europeans (hg2 = 0.191; N = 1,231), which we think can be explained by reduced genetic variation at skin pigmentation loci due to strong positive selection for lighter skin in Europeans [17,21,38].”
From Investigating the case of human nose shape and climate adaptation (2017) · cites this paper as [17]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Effect sizes are attributed to the wrong figure
MinorThe text directs readers to Figure 6a for skin-color effect sizes, but the captions identify Figure 7a as the effect-size panel; Figure 6 concerns allele frequencies and haplotypes.
“and the sum of effect sizes for homozygous substitution at all four loci would shift, in an individual, an amount about the same as ∼1/3 of the total range of skin color we observed (Figure 6a).”
“Figure: Figure 7 Genetic architecture of skin color variation. (a) Effect sizes of the loci associated with skin color.”
Figure 6 names a different HERC2 SNP
MinorThe Figure 6 caption identifies the eye-color SNP as rs1291382, whereas Table 1 identifies it as rs12913832. The caption appears to omit a digit.
“eye [HERC2 rs1291382; (a)]”
“| 15q13.1 | HERC2, OCA2 | rs12913832 | 2.3×10−62 | 2.3×10−27 | −/−/−/− | 0.79 | 0.00 | 0.18 |”
Citations
Cites
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Self-citationMaCH: using sequence and genotype data to estimate haplotypes and unobserved genotypes
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Flagged first, then by citations
1 of the 55 references couldn’t be matched to a known paper.
Research works printed but not linked: 1
- Baleno IC (2001) Povoamento e Formação da Sociedade. In: Albuquerque L, Santos, M.E., editor. História Geral de Cabo Verde. Lisbon, Praia: Instituto de Investigação Científica Tropical, Instituto Nacional de Investigação, Promoção e Património Culturais de Cabo Verde. pp. 125–177.
Cited by
Sorted by citations
The advantages and limitations of trait analysis with GWAS: a review
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Genome-wide patterns of selection in 230 ancient Eurasians
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Metadata
- Authors
- Beleza, S., Johnson, N. A., Candille, S. I., Absher, D. M., Coram, M. A., Lopes, J., Campos, J., Araújo, I. I., Anderson, T. M., Vilhjálmsson, B. J., Nordborg, M., Correia e Silva, A., Shriver, M. D., Rocha, J., Barsh, G. S., & Tang, H.
- Affiliations
- Universidade do Porto (PT)
- Stanford University (US)
- Stanford Medicine (US)
- HudsonAlpha Institute for Biotechnology (US)
- University of Cape Verde (CV)
- Gregor Mendel Institute of Molecular Plant Biology (AT)
- Pennsylvania State University (US)
- Corresponding author
- Beleza, Sandra
- Barsh, Gregory S.
- ORCID
- Venue
- PLoS Genetics
- Publisher
- Public Library of Science (PLoS)
- Published
- 2013-03-21
- Volume
- 9
- Issue
- 3
- Pages
- e1003372
- ISSN
- 1553-7390 (ISSN-L)
- 1553-7404
- PMC
- PMC3605137
- OpenAlex
- W2129233990
- Cited by
- 161
- References
- 55
- Citations by year
- 2026: 6 · 2025: 7 · 2024: 8 · 2023: 10 · 2022: 12 · 2021: 20 · 2020: 11 · 2019: 9 · 2018: 13 · 2017: 20 · 2016: 11 · 2015: 15 · 2014: 12 · 2013: 7
- FWCI
- 8.70
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- PLoS Genetics (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Figshare (submittedVersion, cc-by)
- Funders
- Fundação para a Ciência e a Tecnologia
- National Human Genome Research Institute (T32HG000044)
- National Institute of General Medical Sciences (GM073059, T32GM007790, R01GM073059)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › melanin and skin pigmentation
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Forensic and Genetic Research
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
- Keywords
- skin color, eye color, admixed populations, Cape Verde, SLC24A5, OCA2, HERC2, TYR, SLC45A2, genetic ancestry, heritability
- MeSH terms
- Eye Color, Genotype, Hair Color, Haplotypes, Humans, Skin Pigmentation, Albinism, Oculocutaneous, Polymorphism, Single Nucleotide, Black People, White People, Cabo Verde
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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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